1. Field of the Invention
The present invention relates to long term evolution (LTE) anchor mobility and transferring of LTE anchors when in an idle state.
2. Description of the Related Art
In the 3rd Generation Partnership Project (3GPP), the evolution from the existing General Packet Radio Service (GPRS) network architecture is being studied under the name of System Architecture Evolution (SAE) in order to enhance the capability of the 3GPP system to cope with the rapid growth in Internet Protocol data traffic. SAE is envisioned to accommodate various types of access systems, such as 3GPP access systems and WLAN, and it supports seamless mobility within and across those access systems. As one of the 3GPP access systems, a new radio access system called Long Term Evolution (LTE) is being standardized. A goal of SAE standardization is to accommodate LTE access and provide higher bit rate packet services with seamless mobility capability.
An LTE anchor provides mobility anchor functionality when a user equipment moves from one user plane entity area to another. The LTE anchor is the user plane entity closest to the radio access network (RAN). The LTE anchor terminates packet data convergence protocol (PDCP) and user plane ciphering/integrity protection for LTE access. However, in the 3GPP architecture, it is not specified how the mobility of user plane functions may be accomplished, or further, which functional entities can be changed or relocated when the user is in an idle state or in an active mode. One such functional entity change that is not specified in 3GPP architecture is the LTE anchor change-over or mobility, which is a critical component to the operation of the developing architecture.
One motivation for an LTE specific anchor change-over could be route optimization, for example, if an earlier selected LTE specific anchor is no longer in an optimal path as a result of user mobility. Another motivation for LTE specific anchor change-over may be a failure in the current LTE anchor requiring a transition to substitute for the failing component. Other motivations for LTE specific anchor change-over may be network congestion in the data path to/from the current LTE anchor or a desire to share load more evenly in the network across other LTE anchors. Thus, LTE anchor mobility has a substantial impact on the 3GPP architecture and there is a need to address the LTE anchor mobility issue if the architecture is to be successful.